Method for preparing fatty esters of non-reducing oligosaccharides in the presence of an amide



United States Patent Nathaniel B. Tucker, Glendale, and James B. Martin,Hamilton, Uhio, assignors to The Procter & Gamble Company, Cincinnati,Ohio, a corporation of Ohio No Drawing. Application May 24, 1955 SerialNo. 510,841

12 Claims. (Cl. 260-234) This invention relates to a process forpreparing fatty esters of oligosaccharides, and more especially to thepreparation of fatty esters of non-reducing oligosaccharides, such assucrose.

Many methods of preparing fatty esters of polyhydr-ic alcohols, sucroseand other non-reducing oligosa-ccharides are known and have beenheretofore employed. Among these are: the direct esterification of thealcohol or oligosaccharide and fatty acids; the reaction of the alcoholor oligosaccharide with fatty acid anhydrides; the reaction of thealcohol or oligosaccharide with fatty acid halides; and thereesterificati-on of fatty acid esters with polyhydroxy alcohols.Various disadvantages are identified with these processes such as, forexample, poor yields, excessive time to carry the reaction to thedesired completeness, and excessive temperatures necessary to pro motethe reaction with the attendant adverse effects on the organic reactantsincluding thermal decomposition, charring, discoloration, and the like.

With the foregoing considerations in mind it is an object of the presentinvention to provide a method whereby fatty esters of non-reducingoligosaccharides can be prepared in good yield in a minimum of time andunder reaction conditions which will not substantially adversely alfectthe organic reactants.

Other objects and advantages will be apparent from the followingdetailed description.

We have found that these objects can be accomplished by subjecting tointeresterificat'ion a mixture of a non reducing oligosaccharide and afatty acid ester of an aliphatic primary monohydroxy alcohol or a fattyacid ester of a polyhydroxy alcohol in the presence of certain amides inwhich the reactants exhibit some mutual solubility.

Generally speaking, the invention contemplates reacting the non-reducingoligosaccharide with the fatty acid ester in the presence of an alkalinecatalyst, which shows activity in interesterification reactions, at atemperature in the range from about to about 150 C., and in the presenceof an amide compound of the general formula n-con RII where R is analkyl group having from 1 to 4 carbon atoms, R is either hydrogen or analkyl group having from 1 to 4 carbon atoms, and R" is an alkyl grouphaving from 1 to 4 carbon atoms. The total number of carbon atoms in R,R, and R" should however in all cases be not greater than 7. Followingcompletion of interesterification to the desired degree, the catalyst isinactivated by the addition of water and/or acids such as acetic,phosphoric, citric, hydrochloric, and the like, and the desired reactionproducts are freed of solvent and purified by any suitable means.

The term oligosaccharides is used herein to differentiate the di, tri,and tetra-saccharides as a group, from the polysaccharides which arecomposed of a much greater number of single units. Of theoligosaccharides, we have found that only those of the non-reducingtype, i. e., those having no potentially free aldehyde or ketonic group,are suitable for purposes of this invention. These include thedisaccharides; sucrose, trehalose and glucoxylose; the trisaccharides;raffinose, melezitose and gentianose; and the tetra-saccharide;stachyose. Thus, the oligosaccharides of concern here are non-reducingpolyhydroxy compounds having from 7 to 16 hydroxyl groups per molecule.

The fatty esters which can be employed in the reaction herein concernedare the fatty acid esters of primary aliphatic monohydroxy alcoholshaving from 1 to 16 carbon atoms, for example, methanol, ethanol,hexanol, decanol, dodecanol and hexadecanol, specific examples beingmethylpalmitate, dodecylpalmitate and hexadecylpalmitate. In addition,fatty acid esters of completely or incompletely esterified polyhydricalcohols having from 2 to 6 hydroxyl groups, such as glycol, ethyleneglycol, glycerol, erythritol, pentaerythritol, mannitol, and sorbitolcan be employed. Glycol dipalmitate, glycerol mono-,

di-, and tripalmitate, mannitol partial palmitates, erythritoltetrapalmitate, pentaerythritol tetrapalmitate and sorbitolhexapalmitate are examples of operative fatty esters. in addition, fattyesters of glycosides, such as methyl glucoside tetrapalmitate, can beemployed.

Just as monoand diesters of glycerol can be prepared from thetriglyceride, so incompletely esterified sucrose esters can be preparedin accordance with the present invention by reaction of sucrose withcompletely esterified sucrose. Thus, the reaction of sucroseoctapalmitate with sucrose can be carried out advantageously with theaid of the present invention.

The aforementioned polyhydricalcohols and non-re ducing oligosaccharidesconsidered as a group will for purposes herein be referred to aspolyhydroxy substances.

The length of the fatty acid chain of the esters above designated is notcritical and is dictated primarily by the type of fatty acid materialsource available. For our purposes however we have found that fattyacids containing from about 8 to 22 carbon atoms are most useful. Thus,the mixtures of fatty acids obtained from animal, vegetable, and marineoils, and fats, such as coconut oil, cottonseed oil, soybean oil,fallow, lard, herring oil, sardine oil, and the like, representexcellent andwaluable sources of fatty acid radicals. In the event it isdesired to produce oligosaccharide esters of single fatty acids by thisinvention, then the fatty acid esters of relatively volatile alcohols(e. g. methanol and ethanol), having from about 12 to about 22 carbonatoms can be reacted with the non-reducing oligosaccharide with the aidof the particular amide reaction medium herein covered. 1

The crux of our invention lies in the selection of the solvent whichcomprises the. reaction medium. The choice of solvent isessential to therealization of rapid and efficient interesterification of thenon-reducing oligosaccharide and the fatty ester under the conditionshereinbefore set forth. We have found that in general thenitrogen-substituted amide compounds as hereinbefore defined areeminently suitable as solvents in our process. These compounds promote arapid rate of reaction with minimum catalyst requirements and undergo aminimum of decomposition during the interesterification reaction.

With these amide solvents we have found in general that the rate ofinteresterification decreases with increase in molecular weight of theamide; that solvent volume requirements in the reaction decrease withincreasing solubility of the non-reducing oligosaccharide in thesolvent; and that the solubility of the non-reducing oligosaccharide inthe amide decreases with increase in the number of carbon atoms in thelongest chain of the alkyl groups attached to the amide nucleus.

Although it is evident from the foregoing that the amount of solventrequired for any given interesterification will vary depending upon theparticular solvent which is to be used, the actual amount of solvent isnot critical.

The proportion of amide solvent hereinbefore defined may be varied from/3 to 50 times by weight of the fatty ester employed for reaction withthe oligosaccharide. in any reactionusing dimethylacetamide as thesolvent, and where all variables except solvent ratio are maintainedconstant, for example, the amount of ester formed by theinteresterification Will increase with increase in the amount of amidesolvent employed at the lower levels of solvent usage, i. e., from about/3 to about 1 part of solvent per part of ester. It is to be understood,however, that the solvent usage is normally adjusted depend ing upon theparticular reactants to be interesteriiied. in any event, sufficientsolvent should be used so that the advantages associated with solventusage, e. g. rapid interesterification, may be realized.

Of the relatively large group of amide solvents which come within thepurview of the foregoing generic definition, and which includes suchcompounds as monomethyland dimethylacetamide, diethylacetamide, andmonoand dipropylacetamide, and monobutylacetamide, we prefer to usedimethylacetamide. This solvent not only exhibits the aforementionedadvantages identified with the amide solvents generally but has theadded ad vantage that trace amounts of acetate groups which mayconceivably be introduced into the sucrose ester product from thesolvent are not objectionable. Moreover, dimethylacetamide is at presentthe most readily available of the solvents herein employed.

It would be reasonable to assume, in view of the foregoing generalformula for the amide solvents, that the formyl amide compounds, such asdimethylformamide and monomethylformamide, could be readily substitutedfor the hereinbefore defined amide solvents with comparable results. Webelieve it is appropriate-at this juncture to point out that this is notthe case however.

Although it is true that the formamide derivatives may be used topromote the interesterification contemplated herein their use is notdesirable for a number of reasons. For example, a comparison ofdimethylformamide and dimethylacetamide as solvents in a sucrose-fatinteraction, indicated that the dimethylacetamide was much more stablethan the dimethylformamide under the conditions of the reaction.Stability was determined by amine evo lution during the reaction, thedimethylacetamide solvent showing evolution of 0.75 millimole of amineper mole of solvent (at 150 C. for 20 minutes) and the dimethylformamidesolvent showing the evolution of 2.45 miliimoles of amine per mole ofsolvent under the same conditions. Moreover, carbon monoxide wasundesirably present in the exhaust gases from the reaction indimethylformamide solvent.

We have also found from the aforementioned comparison that thesucrose-fat interaction can be satisfactorily carried out indimethylacetamide at much lower catalyst levels than are necessary withdimethylformamide. Concentrations of .05 sodium methoxide, by weight ofthe fatty material, are suitable with dimethylacetamide the solventwhereas from 0.1 to 0.2% are required for satisfactory interaction whendimethylformamide is the solvent.

Furthermore, dimethylacetamide is effective as a solvent in theaforementioned reaction at from about /3 to about A of the minimum levelusable with dimethylformamide, and, in addition, is more tolerant of thepresence of moisture in the solvent, i. e., a much greater amount ofmoisture may be present in the acetamide solvent than in the formamidesolvent before any appreciable adverse effect on reaction completenessis noted.

We have found too that whereas monomethylacetamide is very effective asa solvent in the sucrose-fat interaction, monomethylformamide promotesonly slight in teraction between these compounds, promoting instead ahigh conversion of the fat to fatty amide. This characteristic of themonomethylformamide to promote other than the desired reaction is ofconsiderable importance insofar as commercial operations are concerned.The commercially available dimethylacetamide and dimethylformarnidesolvents contain as impurities small quantities of the monomethylcompounds and, whereas the monomethylacetamide impurity indimethylacetamide solvent would not affect the interesterification, themonomethylformamide in the dimethylformamide solvent would promote theformation of fatty amide and result in a reduced yield of the desirablesucrose ester.

The proportion of reactants is not critical and is dietated primarily bythe ultimate product which is desired. For example, in the reaction ofsucrose with fatty ester, proportions can be chosen so that from one toall of the hydrogen atoms of the hydroxyl groups of sucrose may bereplaced by fatty acyl radicals. Gr, Where sucrose and a triglycerideare being reacted, proportions can be chosen so that the final productmay predominate in either glycerides or sucrose esters. As a practicalmatter, however, we have found that molar ratios of non-reducingoligosaccharide to fatty ester in the range from about 30:1 to about1:20 are most satisfactory, the proportions being variable within therange depending on the completeness of replacement desired and on thenumber of fatty acid radicals in each mole of ester substance. Thus, forexample, if 0.1 mole of methylpalmitate is reacted with 1 mole ofsucrose under the hereinbeiore defined conditions and at reducedpressure essentially all of the sucrose ester formed will be themonoester. if the molar ratio is changed to 1:1, one obtains a highyield of monester of sucrose, but more diester will be present. Aproduct averaging approximately 2 palmitic acid groups per mole ofsucrose may be obtained with a molar ratio of methylpalmitate to sucroseof 22-1. When molar ratios of 4:1, 8:1 or 10:1 are used the averagenumber of palmitic acid radicals per mole of sucrose obtained may be3.5, 6, or 7.5.

Although our process is illustrated herein principally with the use ofsodium methoxide as the catalyst, effective practice of our process isnot dependent upon the use of any particular catalyst. Rather, anyalkaline molecular rearrangement or interesterification catalyst whichwill promote the interchange of radicals among the reactants of ourprocess is suitable. Examples of usable catalysts are: sodium methoxide,anhydrous potassium hydroxide, sodium hydroxide, metallic sodium, sodiumpotassium alloy, and quaternary ammonium bases such as trimethyl benzylammonium hydroxide. A discussion of other catalysts which are active ininteresterification reactions may be found in U. S. Letters Patent,2,442,532, to E. W. Eckey, column 24, line 18 et seq.

The sodium methoxide catalyst may be advantageously used in our processin amounts from about 0.05% to about 2.0% by weight of the fatty esterwhich is to be reacted, equimolar amounts of other catalysts beingusable. The choice of catalyst and the amount which is to be used are ofcourse dependent upon the particular constituents which are to bereacted.

In the practice of the invention, it was observed that the reaction ratefor a given solvent usage and a given catalyst increased with increasein temperature. With optimum amounts of dimethylacetamide solvent, forexample, and with sodium methoxide as the catalyst, at temperatures ofC., we found that equilibrium was reached within about 5 minutesreaction time and that somewhat longer reaction times were required atlower temperatures. However, substantial ester formation was observed atreaction temperatures as low as 35 -40 C.

Where low temperatures, such as 20 C. are employed for special purposes,longer reaction times are required to achieve desired ester formation.Temperatures above 100 C., such as 150 C. may, of course, be employed,but in view of the high rate of reaction observed in use of the solventsof the present invention, such temperatures may only infrequently benecessary to accomplish the desired ester formation. Generally speaking,with any of the aforementioned reactants, catalysts, or solvents andwithin the ranges of proportions set forth, the process of our inventionis preferably carried out at a temperature in the range from about 80 toabout 150 C.

Although our process is normally carried out at atmospheric pressure, itcan if desired be carried out under reduced pressure, an operation whichat times is decidedly advantageous. For example, when a fatty acid esterof methanol is reacted with sucrose, operation under reduced pressure,such as about 80 mm. of mercury, enables the methanol formed as a resultof the interesterification to be removed from the reaction zonesubstantially as rapidly as it is liberated, thus promoting asubstantially complete conversion of the methyl ester to sucrose fattyester.

Under any of the foregoing conditions we have found that when the fattyesters of polyhydroxy compounds are reacted with a non-reducingoligosaccharide (in the presence of sodium methoxide catalyst) theinteresterification is substantially complete in from about 2 to 5minutes. When, on the other hand, the fatty esters of aliphaticmonohydroxy primary alcohols are reacted with a non-reducingoligosaccharide, a slightly longer time is normally required and we havefound in this latter instance that the reaction is substantiallycomplete in about ten minutes.

No adverse effects have been noted if the interesterification is allowedto continue for as long as one to two hours but from a practicalstandpoint little advantage is gained from such practice. Because of therapidity at which the reaction progresses under the conditions of ourprocess, times of less than two minutes, and even as little as about 30seconds at temperatures of 100-125 C. may be found to be adequate toachieve the degree of reaction, so that the process lends itself well tocon tinuous as well as to batch methods.

Since the reaction of the present invention is an interesterification inwhich sucrose, for example, is reacted with a fatty ester, the resultingproduct of the reaction will constitute an equilibrium mixture ofsucrose, esters thereof, displaced alcoholic substance from the esteroriginally employed, and ester of such alcoholic substance. Thus, iftriglycerides are reacted with the sucrose, then the product of thereaction will contain monoand diglycerides as well as sucrose esters. Ifit is desired to obtain sucrose esters which are not so contaminatedwith original esters and derivatives thereof, then it is preferable toreact volatile alcohol esters such as methyl or ethyl esters with thesucrose and, as suggested above, to conduct the reaction under vacuum sothat displaced alcohol is distilled ofi. High yields of sucrose estersare obtainable in this way and, of course, unreacted volatile esters canbe separated subsequently by distillation to yield sucrose esters ofhigh purity.

One way of determining whether or not ester has been formed when workingwith the oligosaccharides is by observing the optical activity of therecovered reaction product. As is well known, sucrose and otheroligosaccharides have optical activity which may be readily determinedin the usual way by polarimetric measurement. In the present case,specific rotation figures have been determined by means of a RudolphModel 70 polarimeter, using a filtered light source of 546 millimicronswave length. The rotation is measured at room temperature (2527 C.) inpyridine solution at a concentration of about 2% using a sample lengthof cm. Under such conditions of observation, sucrose shows a specificrotation of 100. The esters'formed from sucrose also 6 possess opticalactivity and since the method of recovery, as shown in the examples tofollow, eliminates contamination of the product with water solublesubstances such as sucrose, then any optical activity of the productrecovered is indicative of a content of sucrose ester. For example, themonopalmitate ester of sucrose has a combined sucrose content of 59% anda specific rotation of 59 to 60 under the above conditions.

Although optical activity can not be accepted as an absolute measure ofthe percent oligosaccharide content of the ester unless the exact natureof the ester is known, there is a close correlation between the percentcombined sucrose content and the observed specific rotation. Thus, forexample, the specific rotation of the octa ester of sucrose will besubstantially less than the monoester of sucrose because of its lowercontent of combined sucrose. Moreover, the specific rotation of theproduct will depend on the nature and concentration of theoligosaccharide ester, whatever it is, in the product being measured.Thus, figures for specific rotation, sometimes designated as [a] areindicative of ester formation in the interesterification reaction, thedegree of esterification being indicated by other characteristics suchas hydroxyl value, saponification value, and total fatty acid content asdetermined by procedures well known in the art.

The following examples will illustrate the manner in which the inventionmay be practiced. It will be understood, however, that the examples arenot to be construed as limiting the scope of conditions claimedhereinafter.

rample 1.-51 grams of sucrose and 89.2 grams of a mixture of 80% soybeanoil and 20% cottonseed oil hydrogenated to an iodine value of about 76were introduced into a reaction vessel provided with mechanical stirringmeans. To the mixture were also added 150 cc. of dimethylacetamide and10 cc. of a suspension of about 9% of sodium methoxide in xylene. Themixture was heated to i3 C. and agitated for 20 minutes. After 15minutes the mixture became homogeneous indicating that the reaction hadproceeded substantially to equilibrium. At the end of the 20 minuteperiod, the catalyst was inactivated by the addition of about 3milliliters of a 50% aqueous solution of acetic acid, and the mixturewas then subjected to distillation to remove two-thirds or more of thedimethylacetamide. The residue was dissolved in about 500 ml. of a 4:1mixture of ethyl acetate and n-butanol. This solution was water washedand the washed fatty products were recovered by deodorization at l00-120C. The thus recovered reaction product, was measured for opticalactivity, hydroxyl value, saponification value, and total fatty acidcontent.

In this example 15.2 grams of the sucrose remained unreacted and wasremoved in the water washing. The yield of ester was 118.3 grams andthis product showed a specific rotation of 30.0, a total fatty acidcontent of 66.9 and a hydroxyl value of 357.

Since the only material having optical activity was the sucrose added tothe system, it is clear from the optical activity measurement thatappreciable formation of sucrose ester occurred in the reaction. Thehydroxyl value indicates that the ester mixture included substantialamounts of partially esterified components.

Example 2.-A mixture of 12.5 grams (.021 mole) of rafiinose, previouslydried by azeotropic distillation of a solution of the pentahydrate in amixture of dimethylacetamide and benzene, 12.5 grams (0.14 mole) of thepartially hydrogenated soybean-cottonseed oil mixture employed inExample 1, and milliliters of dimethylacetamide was heated to 100 C. and2 milliliters of a 9% suspension of sodium methoxide in xylene wereadded. The mixture was mechanically stirred. A homogeneous single phaseresulted after two minutes agitation at 100 C.

. After 30 minutes total agitation at 100 C., milliliters of a 50%solution of acetic acid were added to inactivate the sodium methoxiclecatalyst. The resulting product was processed as in Example 1 to recoverthe fatty esters formed in the reaction. The yield was 9.4 grams of aviscous material having a specific rotation of 62.6, a hydroxyl value of365, a saponification value of 134, and a total fatty acid content of60.9. The reaction was successful in producing fatty esters ofraffinose. H Example 3.The process of Example 2 was repeated using 11.4grams (.042 mole) of methyl palrnitate instead of 12.5 grams of thetrigylceride mixture and except that the reaction was allowed to proceedfor two hours instead of 30 minutes. The product recovered after removalof dimethylacetamide solvent and water washing showed an opticalactivity of 47.7, indicating the formation of ralfinose palmitate ester.

Example 4.--3.8 grams (.01 mole) of trehalose dihydrate were dried byazeotropic distillation and to the resulting product were added 5.52grams (.0062 mole) of the triglyceride mixture used in Example 1 and 30milliliters of dirnethylacetamide. The mixture was heat ed to 100 C. and1 milliliter of a 9% suspension of sodium methoxide in xylene was added.The mixture became a homogeneous single phase after a reaction time ofone minute. After 30 minutes reaction time, the catalyst was inactivatedand the reaction product was recovered as indicated in previousexamples. The recovered product was a viscous material and amounted to4.69 grams. Its specific rotation was 63.4, its hydroxyl value was 305,and the total fatty acid content was 67.8.

Example 5.-Iu this example a mixture of 20 grams sucrose, 36 grams ofthe triglyceride mixture employed in Example 1, 200 grams ofmonomethylacetamide, and 4 milliliters of the 9% sodium methoxidesuspension in xylene were heated at 100 C. to effect formation ofsucrose ester. After one minute reaction time, the mixture became asingle homogeneous phase. The fatty ester recovered from a portion ofthe reaction mixture removed at this stage showed a specific rotation of26.6, indicating that about 26% of sucrose ester was present in theproduct.

Another sample of the reaction mixture, removed after five minutesreaction time showed a specific rotation of 29.8, indicating that thereaction to form sucrose ester had almost reached equilibrium after oneminute reaction time.

In an auxiliary example, the same mixture of ingredients was subjectedto a reaction temperature of 5055 C. At the end of 10 minutes thespecific rotation of the recovered ester product was 18 and at the endof 60 minutes reaction time it was 30.1.

Examples 6, 7, 8, 9, 10, 11, and 12.A number of amide compounds comingwithin the scope of the definition hereinbefore given were employed inthe formation of sucrose esters. in each case 10 grams of sucrose, 18grams of the same triglyceride mixture used in Example 1, 100milliliters of the amide reaction medium, and 2 milliliters of themethoxide catalyst suspension were reacted at 100 C. In the followingtable, the results are given, showing substantial production of sucroseesters in all cases.

Specific Rotation After Minutes of Reaction Time Amide Solvent Min.

10 Mill.

diethyl acetamide monobutyl acetamide monoethyl acetamide monomethylbutyrami monomethyl propionami dimethyl butyramide dimethyl acetamideSpecific Rotation After Minutes of Reaction Time Catalyst 1 3 5 15 Min.Min. Min. Min.

Potassium hydroxide 8. 9 23. 2 27. 6 31. 0 Benzyltrimethyl ammoniumhydroxide 20.8 28. 2 29.7 31. 1

Having thus described our invention, we claim:

1. A process for preparing fatty esters of non-reducing oligosaccharideswhich comprises reacting a non-reducing oligosaccharide with a fattyacid ester selected from the group consisting of the fatty acid estersof ali phatic primary monohydroxy alcohols having from 1 to 16 carbonatoms and fatty acid esters of polyhydroxy substances, in the presenceof an interesterification catalyst, at a temperature in the range fromabout 20 to about C., and in the presence of an amide of the generalformula R-CON/ where R is an alkyl group having from 1 to 4 carbonatoms, R is selected from the group consisting of hydrogen and an alkylgroup having from 1 to 4 carbon atoms, and R is an alkyl group havingfrom 1 to 4 carbon atoms, the total number of carbon atoms in R, R, andR" being not greater than 7.

2. The process of claim 1 wherein the non-reducing oligosaccharide issucrose.

3. The process of claim 1 wherein the amide is dimethylacetamide.

4. The process of claim 1 wherein the amide is monomethylacetamide.

5. The process of claim 1 wherein the amide is monoethylacetamide.

6. The process of claim 1 wherein the amide is mono methylpropionamide.

7. The process of claim 1 wherein the amide is dimethylacetamide andwherein the amount of amide is from /3 to 50 times by weight of thefatty ester.

8. A process for preparing fatty esters of sucrose which comprisesreacting sucrose with a fatty acid ester selected from the groupconsisting of the fatty acid esters of aliphatic primary monohydroxyalcohols and the fatty acid esters of polyhydroxy alcohols, all of saidalcohols having not more than three carbon atoms, in the presence of aninteresterification catalyst, at a temperature in the range from thegroup consisting of the fatty acid esters of aliamide compound of thegeneral formula RI RO ON where R is an alkyl group having from 1 to 4carbon atoms, R is selected from the group consisting of hydrogen and analkyl group and R" is an alkyl group having from 1 to 4 carbon atoms,the total number of carbon atoms in R, R, and R" being not greater than7.

9. A process for preparing fatty esters of sucrose which 9 comprisesreacting sucrose with a fatty acid ester of glycerol, in the presence offrom about 0.05 to about 2% of an interesterification catalyst, byweight of the glycerol ester, at a temperature in the range from about80 to 150 C. in a reaction medium comprising essentiallydimethylacetamicle.

10. The process of claim 8 wherein the fatty acid ester is atriglyceride.

11. A process for preparing fatty esters of sucrose which comprisesreacting sucrose with a fatty acid ester of methanol in a reactionmedium comprising essentially dimethylacetamide, in the presence of fromabout 0.05 to about 2% of an interesterification catalyst, by weight ofthe methyl ester, at a temperature in the range .from about 80 to 150 C.and at such a snfiiciently low pressure that 15 10 in the presence of aninteresterification catalyst at a tentperature of about 100 C. in areaction medium comprising essentially dimethylacetamide, inactivatingthe catalyst by acidulation, distilling substantially all of thedirnethylacetamide from the reaction mixture and water-washing theresidue whereby undistilled solvent and unreacted sucrose are removedtherefrom.

References Cited in the file of this patent UNITED STATES PATENTS1,959,590 Lorand May 22, 1934 2,013,034 Cox et al. Sept. 3, 19352,399,959 Tucker May 7, 1946 2,412,213 Groen Dec. 10, 1946 2,587,623Jeanes et al Mar. 4, 1952 OTHER REFERENCES Markley: Fatty Acids,Interscience Publishers, Inc., New York (1947), pp. 291-293. v

U. S. DEPARTMENT OF COMMERCE PATENT-OFFICE CERTIFICATE OF CORRECTIONPatent Noa 2,831,854 Nathaniel Bo Tucker et a1. April 22, 1958 It ishereby certified that error appears in the printed specification of theabove numbered patent requiring correction and that the said Let cersPatent should read as corrected below.

Column 8, lines 64 and 65, strike out "from the group consisting of thefatty acid esters of alisamide compound" and insert --from about 80 to150 C, and in the presence of an amide colnpoui'ld- Signed and sealedthis 24th da of June 1958u (SEAL) Attest:

KARL Ho AXLINE ROBERT C. WATSON Attesting Officer Conmissioner ofPatents

1. A PROCESS FO RPREPARING FATTY ESTERS OF NON-REDUCING OLIGOSACCHARIDES WHICH COMPRISES REACTING A NON-REDUCING OLIGOSACCHARIDE WITH A FATTY ACID ESTER SELECTED FROM THE GROUP CONSISTING OF THE FATTY ACID ESTER OF ALIPHATIC PRIMARY MONOHYDROXY ALCHOLS HAVING FROM 1 TO 16 CARBON ATOMS AND FATTY ACID ESTERS OF POLYHYDROXY SUBSTANCES, IN THE PRESENCE OF AN INTERESTERIFICATION CATALYST, AT A TEMPERATURE IN THE RANGE FROM ABOUT 20* TO ABOUT 150*C., AND IN THE PRESENCE OF AN AMIDE OF THE GENERAL FORMULA 